磷石膏制硫酸铵的反应机理与动力学实验研究

Reaction mechanism and kinetics of ammonium sulfate prepared by phosphogypsum

研究了磷石膏制取硫酸铵的反应机理与本征动力学速率方程,通过理论研究与实验论证发现,上述反应是在磷石膏与碳酸铵的固液界面上进行的,符合缩芯模型。在动力学速率方程参数的测定中,由于磷石膏微溶于水,反应速率近似地认为只与碳酸铵的浓度有关,实验是在低温、低碳酸铵浓度、高搅拌速率以及磷石膏过量的条件下进行的,实验得到了温度为0,5,10℃时的速率常数,同时将不同温度的速率常数进行拟合得到了磷石膏与碳酸铵反应的活化能为37 246.64 J/mol,指前因子为77 033.83 min-1。

The reaction mechanism and the intrinsic kinetic rate equation of ammonium sulfate from phosphogypsum were studied. The reaction was carried out on the solid-liquid interface between the phosphorus gypsum and ammonium carbonate through theoretical research and experimental demonstration. In other words, the reaction mechanism was in accordance with shrink core model. In the determination of kinetic rate equation, the reaction rate was approximately only related to the concentration of ammonium carbonate due to the slightly soluble in water of phosphorus gypsum. Experimental results were obtained at 0 ℃, 5℃ and 10 ~C under the conditions of low temperature, low concentration of ammonium carbonate, high agitation rate and excess phosphogypsum. Moreover, the activation energy of the reaction between phosphogypsum and ammonium carbonate was obtained by fitting the rate constants of different temperatures. The activation energy is 37 246.64 J/tool, and the pre-exponential factor is 77 033.83 min-1.